Ozonizer



reienie 'N a-iaies a I c 2,136,572

' STATS: PM E-N'l I FFlQE Herbert A. Winkclmann and Albert Baird Fri-,daker, Chicago, Ill., assignors to'Marbon Corporation, a corporation ofDelaware No Drawing. Application March 20, 1936, Serial N0. 69,880

Claims. (01. 204-32) v This invention relates to electrical capacitors,former to a source of electrical energy. The

r and more particularly to ozone generators. It, discharge between theozone elements, therefore,

comprises condensers and'ozone generators prowill take place from'dielectricto dielectric. Howvided with an improveddielectrlc material.I v h eh'this is the pr err d r m n One object of this invention is toprovide an and results in advantages, as for example, the 5 improvedtype of capacitor. protection of the electrodes from the ozonizingAnother object of this invention is to provide action of the ozone, itls necessary h t an ozonizer giving a more efficient and economicalelectrodes and dielectric be thus arranged, but production of ozone.they may be so arranged that the discharge will Another object is toprovide a pure ozone sub ak p e, f om dielectric o electrode, or v 10stantially free of oxides of nitrogen. from electrode t electrode h u hn air p. Another object is to provide an ozonizer which although thelatter arrangement gives v ry p r will withstand long and hard usagewithout the r u ts. necessity for replacement of dielectric plates and ep fer e n e elements p e an electrodes due to breakage, or the oxidizingeffect e ec r de ed and enclosed in a ctr c 15 of ozone. composed ofrubber hydrochloride. The com- A further object is to provide good ozoneproplete element give d ozone pr n for duction with relatively lovoltages, 4000 volt operation when it is approximately .062"

A further object is to provide a. dielectric whi h thick, and containsan electrode of .042" thickcan be used in very thin form without dangeroi ness spaced quidi n from the iele tric scr- 20 breakage, therebymaking possible the production faces S0 't re is approx mately .01? ofdielecof a more compact ozonizer or other electrical trio on eachgenerating surftlce- These 0Z0nlZ- capacitor. ing elements are spacedapproximately apart,

-Another object is to provide a dielectric which h y f m a series of i sn in whi h Q will be resistant to penetration by ozone vapor, O o e s ee a e 25 1) Ozone production.

, and'also resistant to'oxidationiby ozone. The. proportions ed are forPurpose Of l vA further object is to provide an ozonizer in tration andmay va y y- However it s on which the temperature of the plates and airbeadvantage of the dielectric material of this inven-- tween the plates.remains relatively cool during tion that it can be readily molded andmade in These and other objects which will hereinafter l operating atrelatively low voltages and the cool become apparent are obtained by theuse of a and efficient production of pure ozone. Higher dielectriccomprising rubber hydrohalides. voltages such as 7500 volts may be usedup to the The preferred dielectric consists essentially of point wheresparking is excessive. With greater rubber-hydrochloride, preferablystabilized against thickness of dielectricthe voltages are neces- 3:,

heat decomposition by means of magnesium sarily increased to obtain goodozone production. oxide, lead oxide, barium hydroxide, barium With glassdielectrics the use oi very thin oxide, or other stabilizer as describedin the 00- plates is impractical due to breakage. Furtherpendingapplication of Herbert A. Winkelmann, more, the conductivity of glassincreases with in- 40 Serial No. 11,665, filed March 18, 1935, nowPatcrease in temperature and varies considerably 4Q rent-2,046,986.during runs due to the formation of hot spots. The ozone generator is atype of electrical ca- Mica is also not highly satisfactory due in partpacitor or condenser comprising, electrodes and to the splitting of thelaminations. Furthermore dielectric plates in which the dielectricplates in the complete enclosure or enveloping of metal 5 stead of beingin contact with each other as in electrodes by glass or mica is'notpractical. Mold- 4.;

condensers, are spaced apart leaving an air space able materials such asBakelite and cellulose ace-'- between them through which an electricaldistate although capable of being molded around charge known as a silentdischarge or corona electrodes so as to give good protection againstefiect takes place, resulting in a conversion of ozone are not highlysatisfactory from the point the oxygen of the air gap into ozone. ofview of efilcient ozone production. Poor yield -The ozone generator maycomprise a series of or-concentration of ozone, puncturing of platesvspaced ozonizer elements, comprising dielectric and the like areobtained with many materials plates having embedded and enclosed thereinwhich might be used as a dielectric for ozonizers, electrodes, a portionof which extends to form including materials having high dielectricterminals which are connected through a transstrength which ordinarilymight be expected to 5| thin form. This results in the possibility oi 30give-good results. In order to be satisfactory a dielectric in an ozonemachine must produce ozone satisfactorily and continue to do so for areasonable length of time, i. e., at least 1000 hours.

We have found that by the use of a heat stabilized rubber hydrochlorideas a a dielectric the ozonizer can be run continuously for over 1000hours without artificial cooling, or drying of the air. Plates of rubberhydrochloride of .01" thickness and less may be used. Throughout suchadverse conditions grams of ozone per kilowatt hour can be readilyobtained.

It is not entirely understood why rubber hydrochloride gives superiorresults. The material has such plastic properties that it flows and doesnot warp or break on expansion and contraction of the embeddedelectrode. It is highly resistant to penetration by vaporand alsoresistant to oxidation. Rubber hydrochloride of inch thickness showsbreakdown voltages of 925 volts per mil. or 36,400 volts per in. m. Ithas a dielectric constant of 3.70, a power factor of .005 and specificresistance in ohms per cm of 10 x 10 However, many materials have higherdielectric strength than rubber hydrochloride, but fail due to heating,so that low leakage is also imperative. Another important item is thatthe dielectric should be free from surface charges as this too willcause heating. Rubber hydrochloride seems to have the necessaryqualifications not only for ozone production but for other electricaluses as, for example, a dielectric in ordinary condensers, and as ageneral insulator.

Although plates of straight unmodified rubber hydrochloride can be usedwith fair results, the best results are obtained by the use of a heatstabilized rubber hydrochloride composition. A composition composed ofrubber hydrochloride parts by weight. magnesium oxide 5-30 parts byweight, gives good ozone production over ,an extended period of time.The magnesium oxide acts as a stabilizer against heat decomposition ofthe rubber hydrochloride. The addition of around 1% or so ofhexamethylene tetraminc with the magnesium oxide is also of advantage.The addition of other heat stabilizers than magnesium oxide as,hydroxide, barium oxide may be done. Barium oxide, particularly whenmixed with magnesium oxide is a very satisfactory compounding agent. Ingeneral the best stabilizers for rubber hydrohalides for ozone purposesare basic or hydrogen chloride reactive metal oxides other than zincoxide, and particularly the metal oxides which form non-hygroscopichalides.

Other rubber hydrohalides than rubber hydrochloride may be used, as forexample rubber hydrobromide. The rubber hydrohalides are preferablysaturated or nearly saturated.

Dielectrics for ozonizers which compare favorfor example, lead oxide,barium ably with glass and mica, although in general not as good as arubber hydrohalide dielectrics are obtained by using rubber chloride,chlorinated the rubber hydrohalides. Other plastic insulatlngmaterialswhich are resistant to ozone and I resistant to penetration byozone vapor, such as vinyl acetate, polymerized chloroprene, althoughnot particularly efllcient as dielectrics in ozone generators areoperable.

Dielectrics in other than plate form may be made, as for examplecylindrical form. Various modifications in shapes, proportions, andother details may be made without departing from the principle of thisinvention. The amounts of heat stabilizer may vary widely. With bariumoxide, particularly, the amount may even be in excess of the hydrogenhalide, without decreasing the eiiiciency, as for example parts byweight of barium oxide per 100 parts of rubber hydrochloride. Thethickness of the plates may also vary widely. In general, however, therubber hydrohalidesare adaptable for efficient use in very thin form, asfor example. .005" and thus have an advantage overother materials whichcannot be used in such thin form without puncturing or splitting.

Paper may be impregnated with rubber hydrochloride, laminated togetherso that an electrode is embedded in the laminated sheet, and used withfair results as an ozonizer element, although such a laminated elementis not a preferred embodiment of this invention.

We claim:

1. In an ozonizer, an electrical assembly comprising at least twoelectrodes having a dielectric therebetween composed essentially of arubber hydrochloride.

2. In an ozonizer, an electrical assembly comprising at least twoelectrodes having a dielectric therebetween composed essentially of anintimate mixture of a rubber hydrochloride and a basic stabilizer.

3. In an ozonizer, an electrical assembly comprising at least twoelectrodes having a dielectric therebetween composed essentially of anintimate mixture 01? rubber hydrochloride and lead oxide.

4. In an ozonizer, an electrical assembly comprising at least twoelectrodes having a dielectric,

therebetween composed essentially of an intimate mixture of rubberhydrochloride and magnesium oxide.

5. In an. ozonizer, an electrical assembly comprising at least twoelectrodes having a dielectric therebetween composed essentially of anintimate mixture of rubber hydrochloride and barium oxide.

